Telephone-exchange system.



L. POLINKUWSKY.

TELEPHUNE EXCHANGE SYSTEM. APPLICATION FILED AUG. I7. I9I4.

l 1 6 1 ,411 Patented N ov. 23, 1915.

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CDLUMBIA PIANDCIRAPH co..wAsHINaTcIN. D. c.

UNITED sTATEs rrENT oEEioE. `p

LIPA POLINKOWSKY, 0F BRUSSELS, BELGIUM, ASSIGNOR TO WESTERN ELCTRIOCOMPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

TELEPHONE-EXCHANGE SYSTEM.

Application filed August 17, 1914. Serial No. 857,130.

line, and relates more particularly to thecontrol of certain of suchswitches of the general type, which operate to select or seize certainelectrically distinguished circuits from a plurality of equivalentcircuits or equipments not so distinguished. Switches of this generaltype are employed in automatic systems for the purpose of selecting' andseizing an idle connecting or trunk line from a plurality of suchtrunks, for selecting and seizing a calling line from a plurality ofsuch lines, or in general whenever it is desired to select and seize aparticular circuit or equipment from a plurality of such circuits orequipments.

More specifically the invention relates to a test circuit or system forswitches ot the type referred to above. It is usual in connection withsuch switches to provide a test circuit which includes a device such asa test relay which is responsive to an electrical condition individualto the terminals of the lines which it is desired to seize, and toprovide devices set in operation by the response of such test relay tocause'the stopping of the switch and the opening of the test circuit,the opening of the test circuit rendering the switch ineffective forseizing other lines. It is also usual to arrange the circuits andapparatus so that the switch will again start in motion if the testrelay does not remain energized a substantial time, but ordinarily noprovision is made to prevent the opening of the test circuit in suchevent, so that the switch may be again started in motion, but will be,due to the opening of the test circuit, thereafter ineffective to seizea line.

VIt is thereforean object of the present invention to not only preventthe stopping of the switch by a momentary energization of the testrelay, but to also provide means for preventing the-switch from beingthereafter rendered ineffective for yseizing other lines. lVith thisobject in view, and inaccordance with this invention, circuits and.apparatus are provided for introducing a.

denite and substantial time interval be-v tween the initiation of theoperationof the] test relay and the opening of the' test .cir-

cuit, so that a momentary energizationy of f ,f i Y. the test relay willnotv alter the test "circuit, i i

and the test relay may thereafter Yoperate to cause the switch to seizea line.

Specincation of Letters Patent. i Patented NOV, 23,

In systems employing switches of thetype' under consideration, amomentary energization of the test relay may occur from various causesother than the contacting ofthe-fswitch with an electricallydistinguished line,-for instance, causes such as grounds,

crosses or short circuits; but the most frequent cause is due to two ormore switches f attempting to simultaneously connect to the sameelectrically distinguished line. In case this should occur in a systememploying the 'l test circuit of this invention, not only will* morethan one switch be prevented from'i tion, which is hereinafterdisclosed, thereV is associated with each switch, in addition t0 a testrelay, a power control relay and a' sequence switch. The circuits are soarranged that the operation of the test relay will cause the operationof the power control relay, which will in turn open the circuit ot themotor magnet of the switch to. stop the switch, and also to establish a`cir-Y cuit for the sequence switch to drive the same through two or moreadjacent positions. The sequence i switch contacts are so arranged thatthe test circuit will not be opened by the sequence switch until afterthe sequence switch has moved through two or more adjacent positions,and as the circuit for the sequence switch will be maintained only aslong as the test relay remains s energized, it follows that if the testrelay fails to remain energized long enough for the sequence switch tomove through at least two positions, the test circuit will not be'Vopened. momentary energization of the test --relay By virtue of thisarrangement, a

, magnet is energized.

can do no more than drive the sequence switch through one position, andhence the test circuit will not be opened by such a momentaryenergization, and the switch will not be rendered ineffective forthereafter seizing other lines.

The invention 1s diagrammatically shown in the drawing as employed inconnection` tical in construct-ion, a description Vof one will suflicefor both. 0n selector switch 1 there is shown a brush carriage carryingbrushes 3, 4 and 5, which are adapted to sweep over, make contact withand test the rows lof terminals of the group of lines in which an idleline is located. The terminals of only two such lines arediagrammatically shown in the drawing, such rows being indicated at Gand 7, it being understood, however, that in such switches as actuallyconstructed, as many rows of terminals are provided in the switch asthere lare lines which it is desired to reach. Also associated with thebrush carriage is a brush 3 which in its normal position makes contactwith the normalfcontact 9, but which is adapted when the carriage isbeing moved to make and break contact with the interrupter plate 10 toground, such brush making contact with the interrupter plate at alltimes, except when the brushes 3, 4 and 5 are exactly centered upon arow of terminals.

The brush carriage is driven from the constantly rotating power shaft 11through the agency of two friction disks 12 and. 13, the friction disksbeing coupled together' by means of the power magnet 14 when such Aholding magnet 15 is also provided which acts, when energized, as amagnetic brake to stop the rotation of the brush carriage.

Associated with the selector switch 1 and individual thereto is asequence or steering switch 16. The construction of sequence or steeringswitches of the type indicated is well known in this art and need not beherein further described. The purpose of the sequence switch 16 is, inits successive positions, to establish the various circuits by means ofwhich the setting and restoration of the selector switch 1 may becontrolled.

The sequence switch 16 is indicated as being capable of. stopping onlyin its first or normal position and in the 7th, 8th and 18th positions,for the reason that it is only necessary for the understanding of thisinvention that the sequence switch should stop in such positions;however, it is obvious that between its 1st and V7th positionsthe'sequence switch may stop as desired to control the selection of thenecessary group of vlines in which the idle line is to be selected inany wellknown manner, and also that between its*l 8th and 18th positionsit may stop to control the establishment of the through or talking`connection, to initiate the restoration of some other switch,or .tobring about other circuit changes.

The selector 2 is provided with brushes 17, 18 and 19 which vare adaptedto travel y over rows of contacts, twoof such rows being indicated at 20and 21. rlhe interrup'ter' brush is indicated at 22, the interrupterplateV at 23, and the normal contact at 24. vThe power magnet of theselector 2 is indicated Y at 25 and the holding magnet at 26. Thesequence switch which is individual to selector 2 is indicated at 27.`8.51.V i

individual to the Selector l is the test relay 28, which is providedwith two` windings, and the power control relay 29. Ak similar testrelay 30,and power control relay 31 is associated with the selector 2.-AConnected with the row Vof terminals 6 in selector 1 and the row ofterminals 2O in@ selector' 2 are three conductors, comprising a line 32.and connected to the row of terminals 7 of selector 1 and row 21 ofselector 2y 9.5 Y 'Y are'three conductors comprising line 33. A relay 34individual to the line 32 is shown connected in the test conductor ofsuch line" and a relay 35 individualfto the line 335 is shown connectedin the test conductor of such line. Y

The invention, however, will bevbetter un'- derstood from thedescription of the'operation thereof which follows: yAssume thatV Y thesequence switches 16 and 27Vhave been icl-5:

magnets 14 and 25v are energized over se`1-15k quence switch springs 160and 270'to start 'f the brush carriages of selectors 1 and 2 in: motion,toV hunt for an idle line. Y Assuming y that'both the lines 32 and 33are idle, a characteristic potential lwill be placed on the terminals 6,7, 2O and 21, such terminals being connected to battery through therelaysA 34 and4 35. If selector 1, for instance," reaches the row ofterminals r6 before se-` j lector 2 reaches the row of terminals 20, 125which are associated xwith sameV line, namely line 32.-the relay 28'willbe energized over a circuit which may be traced from battery throughtherelay 34, terminal 6, brush 5,

sequenceswitclr spring 16.1, left-hand wind-l 1123i l ing of the testrelay 2S, sequence switch spring 162 to ground, provided the sequenceswitch 16 is in either of positions 7 or 8. The test relay 2S will closeits front contact and establish a circuit, which will include theright-hand low resistance winding of the test relay, and the Winding ofthe power control relay 29 to ground. vA branch of the circuit lasttraced includes the sequence switch spring 163, interrupter brush 8 andinterrupter plate 10 to ground, which branch circuit will shunt therelay29 and prevent it from operating until such shunt circuit is openedby the brush 8 falling in between two teeth on the interrupter plate 10which will occur when the brushes 3, @L and 5 are accuutelv centered onthe row of terminals 6. The relay 29 will then operate and kopen thecircuit for the power magnet 1a and also close at its front contact acircuit for the holding magnet 15,y including sequence switch spring164, thus causing the energization of the holding magnet and thestopping of the brush carriage on the rowof terminals 6. The relay 29will also close at its front contact a circuit through the power magnetof the sequence switch 16, and will drive the sequence switch Jfromposition 7 to S, and if the test relay remains energized a sufficienttime, the relay 29 will hold up long enough to drive the sequence switchthrough position 8. It will be observed that in both positions 7 and 8of the sequence switch 16, the test relay 2S will be associated with thetest circuit of the selector and will be in position to respond whensuch selector makes contact with the terminals of an idle line, and thata mo` mentary energization of the test relay will not drive the sequenceswitch through both positions 7 and Q It may easily happen that theselectors 1 and 2 may be simultaneously hunting for an idle line in agroup of lines appearing in both of such selectors and therefore thatthe movable brushes of both selectors may simultaneously reach terminalsassociated with the same line, for instance, the brushes 3, 4t and 5 maymake contact with the row of terminals 6 at the same time that brushes17, 18 and 19 make contact with row of terminals 20, the row ofterminals 6 as well as the row 20 both being connected to line 32, inwhich case the test relay 28 may be energized over the circuitpreviously traced and the test relay 30 may be energized over a circuitincluding the relay 34C, a test conductor of the line 32, terminal 20,brush 19, sequence switch spring 271, lefthand high resistance windingof the test relay 30, sequence switch spring 272 to ground. Thereforethere will be a tendency for both of the relays 28 and 30 to operate,but owing to the fact that they must both be energized over their highresistance windings, the potential'ot1 the battery associated with thetest conductor or" line 32 will be insutlicient to maintain both of thesaid relays energized, so that one of said relays will fall back, or inexceptional cases both of said relays may fall back. However, it mayeasily happen that both of said relays may have been energized longenough to close their front contacts and operate their respective powercontrol relays 29 and 31, in which case the sequence switches 16 and 27would be driven out of position 7 to position 8 and the motor magnets ofthe selectors 1 and 2 would be denergized. ln the case of the relay 28which we will assume held up, this would be the normal operation and thecircuit of the power control relay 29 would be maintained long enough todrive the sequence switch not only from position 7 to position S, butalso through position S. rlhe brush carriage of selector 1 wouldtherefore stop with the brushes 3, L1 and 5 centered on the terminals 6.

In the case of relay 36 which we will assume has fallen back, themomentary energization thereof in addition to momentarily energizing thepower control relay 31 ,and driving sequence switch 27 to position 8also opened the circuit of the motor magnet' 25. The motion of the brushcarriage of the selector 2 may have actually been stopped but when relay30 falls back relay 31 also falls back, and the brush carriage selector2 will again start in its hunting movement. However, the test relay 30was not energized long enough to cause the sequence switch 27 to moveout of position 8, so that the test circuit of the selector is stillmaintained and the selector may still seize an idle line. It is obvious,therefore, that had the test circuit been closed only in the seventhposition of the sequence switch 7 instead of in both the seventh andeighth positions, the selector 2 would have returned to normal withoutbeing able to seize another idle line and the call associated with suchselector would have been lost. The selector 2 having again been startedin motion as above described with the sequence switch 27 in position 8,and having reached the row of terminals 21 associated with idle line 33,the test relay 30 will again operate, and in this case remain energizedover a circuit which may be traced as follows: battery, relay 35, line33, terminal 21, brush 19, sequence switch spring 271, left hand highresistance winding of relay 30, sequence switch spring 272 to ground.closes a circuit for itself including its right hand low resistancewinding and power control relay 31 to ground. Vhen the shunt around therelay 31 is removed when the brushes are accurately centered on theterminals 21 by the opening of the interrupter circuit, the relay 31will operate denergiz- The relay 30 ing the magnet 25, energizing thevholding magnet 26 and driving the sequence switch 27 out of position 8.The brush carriage of selector 2 will thereforefstop and connection tothe idle line will have been made. Both selectors will therefore haveseized idle lines and neither call would have been lost. In case both ofrelays 28 and 30 should fall back, both selectors l and 2 would `beagain started and with their sequence switches in position 8 and unlessthey should both again attempt to simultaneously seize the same linewhich is extremely unlikely` neither call vwould be lost. Still anothercondition under which the test relay associated with a selector switch,of the type herein disclosed, may become momentarily energized withoutthe switch seizing aline may be brought about by the failure of theholding magnetto bring the brush carriage to a stop vbefore the brusheshave overrun the terminals-'in otherv words, the momentum of the brushcarriage may be 'sufficient to carry the brushes beyond a row ofterminais before the motion of the brush carriage is stopped. In thiscase, assuming that the brushes havevcontacted with the terminals of anidle line, and have not been stopped until after they have traveledbeyond such row of terminals, the line and power control relays willhave been momentarily energized, in which case the sequence switch willhave moved only from position 7 to position 8, because as soon as thebrushes leave the row of terminals the line and power control relayswill become denergized. The momentary energization of the test relaytherefore would not render the switch ineffective for seizing otherlines for the reason that as soon as a line relay is denergized theswitch will again start on its hunting movement with the test circuitclosed in the eighth position of the sequence switch.

It is obvious that because two test posi tions are provided on thesequence switch a momentary energization of the test relay from anycause will not disable the selector from thereafter selecting an idleline. The function therefore of the double test position of the sequenceswitch may be stated to be the provision of a time interval between theinitiation of the operation of the test relay and the opening of thetest circuit at the sequence switch, whereby the test circuit is notaltered by a momentary energization of the test relay.

I claim:

l. Ina telephone exchange system, the combination with a selector, of adriving circuit and a test circuit therefor, a test relay in said testcircuit, means controlled by the response of said relay to open saiddriving circuit and to disable the test relay for further testing, andmeans for interposing a time interval between the opening of the.

driving circuit and the disabling of the test relay. Y

2. In a rtelephone exchange system, the combina-tion with a selector, ofa driving circuit and a test circuit therefor, a relay in said testcircuit and means controlled by said relay when actuated to o-pen thedriving circuit, Vandl means operated onlyin case said relay remainsactuated a predetermined in- 'i Y Y `terval to disable the selector forVfurther test-` ing. x 3. In a telephone exchange system, the

combination with a selector, of a driving cir-V cuitJ therefor, a testcircuit, a relay con` trolled lthereby which when actuated-opens so .c

the driving circuit, and means operated only L in case said relayremains actuated a predejk termined interval to open the test circuit.

4. In a telephone exchange system, the

combination with a selector, of a` sequencel switch associatedtherewith, a test circuit for said selector maintained closed by said csequence switch in a plurality of successive positions, and a circuitfor advancingy said sequence switch maintained closed as long as saidtest circuit is closed, wherebytrol of said driving circuit andadaptedfonly in case it remains actuated a predetermined interval tocau'sesaid sequence switch to open said test circuit.

6. In va vtelephone exchange system, theV positions indiioo combinationwith a selector, of a sequence;`

switch associated therewith, a `driving cirilo two successive positionsof said sequence.' switch, a test relay therein, anda relay con-1 cuitfor the selector, a test circuit closed lin trolled by said test relayandwhich when actuated upon the energization of said test relay when theselector connects with an" idle line is adapted to open the drivingcircuit and onlywhen maintained energized a predetermined interval, toadvance the sequence switch through both positions individual to thetest circuit.

7. In a telephone exchange system, the combination with a selector, of`a-'sequence switch associated therewith, a driving'cir-r cuit and atest circuit for the selector, said test circuit being closed through aplurality of successive positions of said sequence switch, and a testrelay in said test circuitv adapted upon its vresponse toA move saidsequence switch throughv a plurality of positions individual to thetestvcirc'uit and if re stored prematurely to hold the sequence switchin one of the succeeding test positions and to reclose the drivingcircuit of the selector for further testing movement.

8. In a telephone exchange system, the combination with a selector, of asequence switch associated therewith, a driving circuit and a testcircuit for the selector, said test circuit being closed through aplurality of successive positions of said sequence switch, and a testrelay in said test circuit adapted when energized to movesaid sequenceswitch through a plurality of positions individual to the test circuitand if restored prematurely to hold the sequence switch. in one of thesucceeding test positions and to reclose on its back contact the drivingcircuit of the selector for further testing.

9. In a telephone exchange system, the

combination with a plurality of automatically operating switches, aplurality of lines multiplied thereto, a driving circuit and a testcircuit for each such switch, and a relay controlled thereby adaptedwhen actuated upon connecting with an electrically distin guished lineto open the driving circuit and, if maintained actuated sufficientlylong, to render ineffective the test circuit, the potential on such linebeing insufficient to maintain more than one relay excited sufficientlylong to render its testing circuit ineffective.

In witness whereof, l hereunto subscribe my name this 28th day of JulyA. D., 1914.

LIPA POLINKOWSKY. Witnesses:

F. T. WOODWARD, H. TUCK SHERMAN.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. G.

